Cooking device



Patented Mar. 8, 1938 UNITED STATES PATENT oFFlcE March 6 Claims. (Cl. 21B-19) This invention relates to cooking devices more particularly to the type in which means is provided to prevent over cooking.

Objects of the invention are: To provide an improved cooking device having means incorporated therein for sensing the occurrence of such conditions as indicate that cooking should be terminated;

4 To provide a cooking device having a trans- 10 lating device therein operable in response changing conditions within the food being cooked;

To provide a cooking device having means responsive to change in the amount of reiiected light from the food for controlling a translating device;

To provide a generally improved cooking device ior terminating the cooking period, or signalling that the cooking period should be termnated, dependent on the condition of the food o itself rather than on an arbitrarily set time .measuring device or an energy measuring device.

A specific embodiment oi the invention is illustrated in the accompanying drawing, in which:

Figure 1 is a horizontal 'cross section of a toaster embodying a preferred form of the present invention on line of Figure 2.

Figure 2 is a vertical cross section on line 2-2 of Figure i, and v so Figureaisacrosssectiononlinel-Iof Figure 1.

In the embodiment of the invention shown in the drawing there is disclosed an electric toaster in which the determination of the end of the toasting period depends on the color of the toast. A base |02 supports a housing |54 in which are mounted a pair of conventional electric heating elements IUS. Pivoted at |42 is an arm lili having a linger piece I|2 at its opposite end. Between the heating elements |56 and at either side of the arm ||5 are two rows of vertical rods ||4 which form a grill to keep the bread properly spaced from the heating elements. Blidably mounted on the four outermost rods is Y a toast carrier H5. A link ||2 pivted to the toast carrier ||5 and to the arm ill enables the two to move up and down together. A spring |20 urges the arm ill and toast carrier to their uppermost position. A latch bar |22 of nonso magnetic material slides through the hollow core' of an electro-magnet |24 mounted on the base |52 by a U-shaped bracket |26. The latch bar |22 has a nose |28 adapted to engage over the top of the arm III to hold it in depressed posia5 tion.s A sprlngw haspne end abutting high potential direct current to the cell |52. A casing contains a relay oi the electronic the U-shaped extension |22 of latch bar |22 and its other end abutting against an adjusting screw |34 mounted in the side of the housing |54. The opposite end of the latch bar |22 carries an armature IIB in operative relation to the electromagnet |24. A stop |34 pressed out of the housing |44 limits the spring lurged movement of latch bar |22 to Just the amount necessary to completely free the ar'm ill. Mounted on an insulating block |45 is a pair of contacts |42 m adapted to be closed when armature |35 is retracted and to be opened when armature |35 is attracted.. The contacts |42 are connected to a signal light |44 mounted in the base |52 behind a glass window |45. An opaque screen |48 has 15 a window |55 therein so arranged that it allows light reflected from the bread 't tall on the light window .oi a photo-electric' cell |52.

The photo-electric cell |52 may be connected in circuit in various ways well known in the art. Preferably it is connected to a power pack con- 20 tained in the casing: |54. This power pack may be similar to those used in radio receiving sets oi the so called all-electric type and supplies a type for amplifying the current passing the cell |52, the output of the relay goes directly to the magnet |24. It is obvious that the cell |52 may be connected in circuit in other ways depending 30 c-n the sensitivity o! the cell used, the type oi current supply with which the toaster is designed to be used, etc. For example, ii a very sensitive cell is used the relay |55 may be omitted and if the toaster is designed for operation from, a suit- 3, able source of direct current the power pack |54 may also be omitted in which case the cell |52 and magnet |24 may be connected in series with the source o! current for the heating elements |55.

Inoperationasiiceoibreadisplacedinthe holder ||5 and the arm ||l isdepressed. The light of the heating element |55 is reilected from the slice of bread to a fairly high degree becaime the bread is white, or if brown bread is used it is lighter in color than when fully toasted. This a relatively high energization of the magnet |24. While the arm ill is still held manually the screw |34 is adjusted to the point where the spring |25 just overcomes 50 the attractive force oi magnet |24. The screw is then backed ci! a small amount depending on the color oi the finished toast which is desired. The magnet then attracts armature l moving latchbar |22 into latching position. The arm 55 H0 will now remain in depressed position until the toast browns to a point where the light reilected therefrom is so far reduced that the magnet IN is no longer able to hold armature |36 against the force of spring |39.- curs latch in i's released and arm together with the carrier lli toast by the spring |20. Signal i is also lighted by closure of contacts M2. It will be seen that magnet |24 is able to hold the arm lill down only as long as a certain amount oi light is reilected from the toast depending on the setting oi' screw |34. Thus the toast is always thrown up when it reaches the desired color regardless of the relative freshness of the bread or the temperature oi the heating elements.

The invention may be also embodied in a toaster in such a manner as to depend on reiiected light from the cell |52 may be so podtioned as to receive light equally from both sides of the toast through separate windows such as lill and provided with suitable reflectors to converge the light rays on the single cell. Alternatively two cells may be used, one on each side oi the bread, the cells being connected in series or parallel to the relay |56 i! such be used, or being connected to separate relays arranged to control the heating elements IIB separately. The latter arrangement presents the advantage that a slice of bread which is drier on one side than the other may be toasted to the same color on both sides.

It will be seen that a cooking device has been provided wherein the time at which cooking is to cease is determined by the occurrence of a certain predetermined condition of the lood itself. Various modiilcations will suggest themselves to those skilled in the art and it is to be understood that the scope of the invention is limited by the scope of the appended claims, rather than by the specific embodiments illustrated and described as examples of devices embodying the invention.

I claim:

1. An electric toaster comprising in combination an electric heater, means for holding bread in a stationary position adjacent the heater to be toasted, a light-sensitive cell, a screen adapted to shield the cell from light rays emanating from the heater directly but to pass light rays reflected from the bread, and means controlled by the cell for moving the bread to a position remote from the heater.

2. An electric toaster comprising in combinaboth sides of the toast. Thus tion an electric heater, means for holding bread in a stationary position adjacent the heater to be'toasted, a light-sensitive cell, a screen adapted to shield the cell from light rays emanating from the heater directly but to pass light rays reilected from the bread, and means controlled by the cell for signalling the end o! toasting.

3. In a domestic toasting device for table use for toasting at one operation a quantity of food having the characteristic that in its completely toasted state it has developed a permanent alteration in the surface color of the food which bears a definite relation in amount to the amount o! toasting regardless of variations in toasting conditions, the combination of a frame, a heating element disposed in the frame, means for holding a .quantity oi food in a position to be toasted by the heating element, and means for signalling the end of the toasting operation including a device which is responsive solely to said color alteration oi the lood as it is being toasted and which is affected solely by said color alteration and a signal mechanism controlled by said device.

4. In a domestic toasting device for table use for toasting at one operation a quantity of food having the characteristic that in its completely toasted state it has developed a permanent alteration in the surface color of the food which bears a definite relation in amount to the amount of toasting regardless of variations in toasting conditions the combination oi a frame, a heating element disposed in theframe. means for holding a quantity of food in a position to be toasted by the heating element, and means for terminating the toasting operation including a device which is responsive solely to said color alteration of the food as it is being toasted and which is ailected solely by said color alteration. and mechanism for interrupting the toasting operation controlled by said second device.

5. In a bread toaster provided with a heating element, a light sensitive element responsive to the surface color of the bread being toasted. and means operated thereby for terminating the toasting of the bread slice when a predetermined surface color has been attained.

6. In a bread toaster provided with a heating element, a light sensitive element responsive to the surface color of the bread being toasted, and signaling means operated'thereby when a pre- 'determined surface color has been attained.

RALPH L. TWEEDAIE. 

